Packaging and transport of food are important components to maintaining freshness and reducing damage to food before and after food gets to the consumer. For example, vegetables, eggs, and baked goods often need to be protected within their packaging to compensate for any rough transport. If the food is damaged, it is no longer appealing and, sometimes, no longer useable.
Another example of a common grocery staple is fruit, wherein the variety, quality and quantity of fruit vary by season, location of retail sale, and perishability of a given fruit. Food retailers typically seek to offer a wide choice of fruit products to their customers notwithstanding difficulty and cost. All types of food pose unique availability and transport challenges. For example, many berries are only available at certain times of year and only in certain locations. Further, as a group, berries easily bruise and spoil and/or develop mold from exposure to excess moisture.
To address the above issues, growers and wholesalers use specialized plastic containers, such as plastic clamshells or tills that are assembled by cutting holes in thermoformed parts. These plastic containers provide physical protection for the contents and have vents in them to allow for drainage and airflow.
To make the plastic containers, manufacturers use a punch and die assembly, wherein the punch and die assemblies are guided to each other using a set of pins. The current standard punch assembly is comprised of a punch holder, several punches, and a plate on the outside of the assembly that mounts against the holder and holds the punches in place. The die assembly is comprised of a die with a plurality of holes that the punches mate to. Several die assemblies then mount to a larger plate to enable several thermoformed parts to be cut simultaneously.
Standard punches have a number of issues that lead to problems and cost issues in the manufacturing process and in the resulting containers, such as: poor stability; thin blades; uniform thickness; attachment too far from the blade; and excessive flexing. These drawbacks result in punches that break easily. Additionally, it is difficult to replace the punches because the entire punch assembly must be taken apart to replace one punch. Another drawback is that the machines that the standard punch and die assemblies attach to easily damage the assemblies and thereby increase maintenance requirements for the assemblies. When the punch assemblies are damaged, they do not cleanly cut the vents and therefore, the plastic containers have rough-cut vents (i.e., chads) that, for example, cut the fruit or affect the roots of the plant. Sometimes, the parts of the plastic container that are supposed to be cut out remain in the container with the food creating a safety issue. Un-removed chads can also adversely affect how the product moves through the automation systems. Further, they present potential issues if consumers ingest them.
A new punch assembly is needed with punches that are more resistant to damage. Further, a punch assembly is needed that has punches that, if damaged, can be more easily replaced.